Antioxidant activity of high-density lipoprotein (HDL) using different in vitro assays

Abstract

The role of HDL in reverse cholesterol transport is well known but other atheroprotective
mechanism, e.g. antioxidant capacities of HDL is not clear. The aim of this study is to
determine the effects of different doses of HDL on antioxidant activities assay. HDL was
isolated from plasma by single step-ultracentrifugation. The antioxidant activity of different
doses of HDL were measured by ferric thiocyanate (FTC), 2,2-diphenyl-1-picrylhydrazyl
(DPPH) and dichlorofluorescein (DCF) tests. Coincubation of HDL with LDL showed longer
lag time and lower reaction rate in a dose-dependent manner compared to LDL alone (p<0.05). HDL had inhibitory effects on radical oxygen species (ROS) production but did not exhibit free radical scavenging activities. HDL is a potent antioxidant in terms of inhibition of lipid peroxidation, ROS production and LDL oxidation. These may to some extent add to the
antiatherogenic beyond reverse-cholesterol transport properties of HDL.

Keywords: high-density lipoprotein; reverse cholesterol transport; apolipoprotein A1;
antioxidant; in vitro.